Gas/liquid interfacial preparation of polyamide fibrids

ABSTRACT

Fibrides of synthetic heterochain polymers are produced by a non-equilibrium polycondensation of an aqueous alkaline solution of bifunctional compounds supplied into the reaction zone as a continuous stream oriented in the horizontal plane of the reaction zone to be acylated with diacylchlorides of dicarboxylic acids in the state of a superheated vapor with a carrier supplied into the reaction zone in the vertical plane, the contacting of the reagents being effected in a cross-current stream under shear stress conditions. 
     An apparatus employed for carrying out the process for producing fibrides of synthetic heterochain polymers includes a vertically mounted cylindrical housing comprising a reaction chamber provided with means for admitting the liquid phase of the starting products thereinto as a continuous flow oriented in the horizontal plane of the reaction chamber; a chamber for generating the gas phase of the starting products positioned under the reaction chamber, and means for removing the reaction products from the reaction chamber provided in the upper part of the latter. 
     The present invention is useful in the manufacture of synthetic paper for electroengineering applications, in aviation engineering, fuel filters for diesel engines, in the production of plastics, and non-woven materials in the textile and light industries.

The present invention relates to the production of polymeric materialsby the method of non-equilibrium polycondensation at the gas-liquidinterface and, more specifically, it relates to a process for producingfibrides of synthetic heterochain polymers and apparatus for carryingout this process.

FIELD OF THE INVENTION

The present invention is useful in the manufacture of synthetic paperfor electroengineering purposes and as a construction material inaviation engineering; fuel filters for diesel engines; in the productionof plastic articles; and non-woven materials in the textile and lightindustries.

BACKGROUND OF THE INVENTION

Known in the art are processes for producing fibrides which are based oneffluence of viscous solutions of polymers into a settler at a shearstress created, for example, by stirring (cf. U.S. Pat. No. 2,988,782,1961; U.S. Pat. No. 3,068,527, 1962; British Pat. No. 959,743, 1964;Australian Pat. No. 261,184, 1965, USSR Inventor's Certificate No.256154, 1969, Cl. D 01 F 6/00).

These prior art processes have disadvantages residing in theirmulti-stage character and the necessity of using large quantities oforganic solvents and settling agents.

Known in the art is a process for producing fibrides in the course ofsynthesis of polymers under foam conditions with the supply of themonomer in the liquid phase, for example hexamethylenediamine, directlyinto the reaction zone of the reactor. The gas flow carried by aircontaining the monomer, for example terephthalic acid dichloroanhydride,is fed in an aerosol state into the reaction zone from the bottom. Whenthe reacting phases contact, there occur chemical processes ofpolycondensation and neutralization of the evolving low-molecular weightsubstance, for example hydrogen chloride. Besides, in a highly turbulentreaction mass converted, by the kinetic head of the gas phase, to amobile three-phase foam, the process of fibride-formation occurs to acertain extent, due to stretching of the resulting gel-like film of thepolymer by the above-mentioned gas flow. The reaction mass containing:the synthetized polymer of a broad particle size and particle shapes,common salt as the product of neutralization of the low-molecularsubstance; water; an excess of hexamethylene and alkali; air is movedalong the reactor towards the separation zone in the vertical planefollowing a complicated path. After the separation zone, the inert airsaturated with vapors of the liquid phase is delivered to cooling andthen exhausted into the atmosphere. The aqueo-alkaline suspension of thepolymer after separation is subjected to filtration. The filtrate isrecycled to the process with the view to utilize a excessive diamine,while the polymeric fibrides are washed, squeezed and packed (see theReport of the Kalinin Polytechnical Institute No. 7403815 "Process forthe synthesis of polymers under foam-formation conditions", 1975, p. 36,deposited in VINITI, state registration No. 74035815, inv. No. 466424,23.02.76).

This prior art process has disadvantages residing in a low yield offibrides not exceeding 50-60%, their small size, insufficient molecularweight, non-uniformity of the polymer relative to the molecular weightand particle size, complexity of the process flow-sheet and difficultiesof conducting the same under continuous conditions. Furthermore, theapparatus employed in the process necessitates additional means forfractionation of the product.

Also known is a process for producing polyamide fibrides by way ofgas-liquid interphase polycondensation of haloanhydrides of dicarboxylicacids with bifunctional compounds (cf. USSR Inventor's Certificate No.632766 of July 21, 1978). In this process the formation of fibridesoccurs simultaneously with the synthesis of the polyamide from themonomers passing into the reaction zone in the liquid and gas phases.The gas stream containing the monomer such as terephthalic aciddichloroanhydride is passed, in the aerosol state from the stage ofgeneration of the gas phase, into the reaction zone of the reactorthrough a perforated partition provided in the reactor between the zoneof generation and the reaction zone; the free cross-section of thepartition being equal to 25%. This gas stream is contacted with theliquid phase containing the monomer, for example hexamethylenediamine,supplied in the form of small drops by means of a mechanical nozzlepositioned along the reactor axis above the aforementioned perforatedpartition. In the counter-current contacting phases there occurs, due tohigh kinetic energy of the gas stream, a phase inversion and theformation of a highly-turbulent layer of a movable foam having ahighly-developed surface area whereupon chemical reactions ofpolycondensation and neutralization of the evolving hydrogen halide takeplace. At the same time, in the foam layer due to shear forces thereoccurs the formation of fibrides which are delivered, along with thereaction mass, by means of the kinetic gas stream to the zone ofseparation and defoaming, whereafter at the outlet of this zone they aresubjected to filtration, washing, squeezing and packing.

However, the known process for producing fibrides with thenozzle-dropwise distribution of the liquid phase has certaindisadvantages complicating operation of the apparatus and impairingquality characteristics of the product. The absence of the totaloverlapping of the cross-section of the reaction space by a continuousfilm part of the jet upon dropwise distribution creates non-uniformityof distribution of the liquid phase, local "breakthrough" of the monomerfrom the gas phase, decrease of the yield and molecular mass of thepolymer. The aerosol state of the gas phase monomer does not provide fora uniform concentration of the monomer and strict equimolarity of themonomers in the reaction zone.

Known in the art are apparatus for physico-chemical and heat-exchangeprocesses comprising a housing with a horizontal perforated partition,inlet pipe or a throttle valve for the supply of the starting componentsinto the reaction zone, the outlet pipe for the discharge of the gasphase, as well as receiving and draining boxes for the liquid phase (seein book "Foam Conditions and Foam Apparatus", ed. by prof. I. P.Mukhlenov and prof. E. Ya. Tarat, Leningrad, "Khimija" Publishing House,1977, pp. 16-20).

In the known apparatus there are no means ensuring the possibility forcarrying out polycondensation processes, i.e. there is lack of anassembly creating conditions for generating a gas phase, regulardistribution of the liquid phase, thus eliminating the use of liquid andsolid monomers under normal conditions in the gas phase to obtainfibrides.

Known is an apparatus for the synthesis of polymers by the gas-phasepolycondensation method which consists of three units: gas-phasegenerator and a reaction chamber partitioned by means of a perforatedwall with the live cross-section of 25%, and a centrifuge foamsuppressor. The diameter of the reaction chamber and evaporator of thegas-phase generation unit is 100 mm. To introduce the liquid phase andremove the polymer suspension, the reaction chamber is provided withcorresponding pipes mounted in its side walls. Compensation of heatlosses is ensured by means of a heating mantle provided at the outersurface of the reactor (cf. Report of the Kalinin PolytechnicalInstitute No. 74035815 "Process for the Synthesis of Polymers by theMethod of Polycondensation under Foam-Formation Conditions", 1975, pp.48-55, deposited in VINITI on Feb. 25, 1975, state registration No.74035815, entry No. B 383154). However, due to the specific character ofdistribution of the liquid phase over the cross-section of the reactorover the partition this prior art apparatus has certain disadvantages.The polymer produced in this apparatus has a structural non-uniformity,contains a substantial portion of a low-molecular powder-like fractions,and features a relatively low average molecular weight and a small yieldof fibrides. When the apparatus operation is stopped, the polymersuspension accumulated in the expander of the foam depressor dropsthrough the perforated partition, contaminates the throttle valve andnozzle of the unit for the gas-phase generation, thus necessitatinglabor-consuming operations of dismantling and cleaning of the apparatusand increasing operating costs of the plant as a whole.

Also known are diffuser-foam apparatus containing no partitions andintended for carrying out the processes of heat and mass transfer underhighly turbulent conditions. Such apparatus has a verticalconically-shaped diffuser with a narrow neck, whereinto gas is fed. Thespraying liquid is introduced into the upper enlarged section of thediffuser. The advantage of the apparatus resides in the absence ofclogging with dust (cf. in book "Foam Conditions and Foam Apparatus",ed. by prof. I. P. Mukhlenov and prof. E. Ya. Tarat, Leningrad,"Khimija" Publishers, 1977, p. 234).

However, this prior art design of the apparatus does not make itpossible to carry out chemical processes of polycondensation in anintensive hydrodynamic stream to produce fibrides.

It is an object of the present invention to provide such a process whichwould ensure a full formation of a synthetic polymer to fibrides with anincreased molecular mass and the same particle size over the entirecross-section of the reaction zone.

It is another object of the present invention to provide such a processfor producing fibrides of synthetic heterochain polymers which wouldmake it possible to simplify filtration of the suspension of theobtained product and washing of the polymer.

It is still another object of the present invention to provide such anapparatus for carrying out the process for producing fibrides ofsynthetic heterochain polymers which would make it possible to increasethe efficiency of utilization of the working space of the reaction zoneof the apparatus.

It is a further object of the present invention to provide such anapparatus for carrying out the process for producing fibrides ofsynthetic heterochain polymers which would make it possible to eliminateexhaust of pollutants into the environment.

SUMMARY OF THE INVENTION

These objects are accomplished by the production of fibrides ofsynthetic heterochain polymers by a process involving non-equilibriumpolycondensation of an aqueous alkaline solution of bifunctionalcompounds to be acylated with diacyl chlorides of dicarboxylic acidsbeing supplied into the reaction zone and subsequent recovery of thedesired product. In accordance with the present invention, into thereaction zone there are fed an aqueous alkaline solution of thebifunctional compounds as a continuous stream oriented in the horizontalplane of the reaction zone and dichloroanhydrides of dicarboxylic acidsin the state of a superheated vapor with a carrier being supplied in thevertical plane, the contact between said reagents being effected in acrosscurrent under shear stress conditions.

The present invention makes it possible to use heat-resistant fibridesof aromatic and aliphaticaromatic heterochain polymers suitable for themanufacture of synthetic paper for electroengineering application, ClassF; Their manufacture avoids the use of organic solvents and scarcesettling agents and the production cost of the resulting fibrides ascompared to phenyl fibride (based on polymetaphenyleneisophthalamide) isreduced by more than 15 times. The yield of fibrides based on theresulting polymer is equal, owing to the present invention, to 100% andthe molecular mass of the polymer is increased by 1.5-2 times. Theprocess according to the present invention makes it possible to ensureuniformity of particles of the produced fibrides. Furthermore,uniformity of size and shape of polymeric particles makes it possible toeliminate from the process, the stage of fractionation of the polymerand deliver the entire aqueous suspension of the polymer directly tofiltration and washing.

According to the present invention, it is advisable to use superheatedsteam or air as the carrier of superheated vapor of dichlorodiacylchlorides of dicarboxylic acids.

The use, as the carrier, of superheated steam or air ensures theproduction of fibrides featuring high quality characteristics at a highyield value. At the same time, the use of steam eliminates pollution ofthe atmosphere with harmful exhausts, and avoids condensation and foamsuppression.

To increase productivity of the process according to the presentinvention by 25 times as compared to the prior art process, it isadvisable that the concentration of diacyl chlorides of dicarboxylicacids supplied into the reaction zone be equal to 0.1-5 mol/m³ of thecarrier.

To enhance productivity of the process for producing fibrides andincrease molecular mass of synthetic heterochain polymers by 1.5 times,it is advisable that polycondensation, according to the presentinvention be conducted at a pressure of from 0.5 to 2 atm and atemperature of from 90° to 105° C. The linear speed of the carrier ofdiaryl chloride of dicarboxylic acids is within the range of from 2 to12 m/sec, and the speed of injection of the continuous stream of theaqueo-alkaline solution into the reaction zone is 0.5 to 6 m/sec.

An embodiment of the present invention is that in carrying out theprocess for producing fibrides of synthetic heterochain polymers, use ismade of an apparatus comprising a vertically mounted cylindrical housingwith a reaction chamber and a chamber for generating the gas phase ofthe starting products positioned under the reaction chamber with meansfor supplying the liquid and gas phases into the reaction chamber andmeans for withdrawing the reaction products from the reaction chamber.In accordance with the present invention in the reaction chamber meansare provided for introducing thereinto the liquid phase of the startingproducts as a continuous stream oriented in the horizontal plane of thereaction chamber and in the generation chamber means are provided forintroducing the gaseous phase of the starting products in the verticalplane.

In accordance with the present invention, it is advisable that the meansfor introduction of the liquid phase contain a shell coaxially mountedoutside the reaction chamber at such a distance from the reactionchamber that between the outer wall thereof and the inner wall of theshell a cavity is formed communicating with the reaction chamber througha clearance made in the lower portion of the reaction chamber and havinga constant height equal to 0.02-0.06 of the diameter of the reactionchamber. The latter is also provided with means for ensuring creation ofthe required dynamic head of the gas phase at the point of its contactwith the liquid phase.

Furthermore, according to the present invention, it is desirable thatthe above-mentioned means be made as a horizontal perforated partitionwith a live cross-section of from 18 to 40%, said partition being underthe above-specified clearance at a distance therefrom of at least 0.015and at most 0.1 of the height of the reaction chamber.

In accordance with the present invention, it is also advisable that thismeans be made in the form of two tapered cones positioned inside thereaction chamber and shaping it, said tapered cones being connectedtherebetween in the site of the minimum diameter with the formation, attheir joint, of a clearance having its height constant over the entirediameter of the tapered cone and equal to 0.02-0.06 of the value of themaximum diameter of the cone. The ratio of the minimum diameter of oneof the tapered cones to its maximum diameter is equal to 2.5-2:1 and theratio of the height of the tapered cone to its minimum diameter rangesfrom 4:1 to 5:1.

Furthermore, in accordance with the present invention it is desirablethat the means for introducing the liquid phase have a mechanical slitnozzle with a guide angle opening of from 110° to 180° mounted along theaxis of the reaction chamber in such a manner that the slit of saidnozzle be positioned at a distance of from 0.1 to 0.04 of the height ofthe reaction chamber from the horizontal perforated partition mounted inthe lower part of the reaction chamber having a live cross-section offrom 18 to 40%.

The present invention is further illustrated by the following detaileddescription of the process for producing synthetic heterochain polymersand the apparatus for carrying out this process with reference to theaccompanying drawings, wherein:

FIG. 1 shows the apparatus for the production of fibrides of syntheticheterochain polymers (elevation view);

FIG. 2 is a view of another embodiment of the apparatus for theproduction of fibrides of synthetic heterochain polymers (elevationview);

FIG. 3 is still another embodiment of the apparatus according to thepresent invention for the production of fibrides of syntheticheterochain polymers (elevation view).

DETAILED DESCRIPTION OF THE INVENTION

Described hereinbelow is the process for producing fibrides of syntheticheterochain polymers, e.g. fibrides of polyhexamethyleneterephthalamide,polyhexamethyleneisophthalamide, polymetaxylyleneterephthalamide,polyhexamethyleneoxamide.

The process according to the present invention is based on anon-equilibrium polycondensation of an aqueous alkaline solution ofbifunctional compounds to be acylated with diacyl chlorides ofdicarboxylic acids. The liquid phase monomers to be acylated can bediamines and dihydric phenols.

As the diamines, use may be made of aliphatic diamines such asethylenediamine, tetramethylenediamine, hexamethylenediamine,dodecamethylenediamine, a mixture of ethylenediamine withhexamethylenediamine; cycloaliphatic diamines such as piperazine,N,β-aminoethylenepiperazine, methylpiperazine; aromatic diamines such asmetaxylylenediamine, para-xylylenediamine, and a mixture of para- andmeta-xylylenediamines.

As the dihydric phenols, use can be made of, for example,4,4'-dihydroxydiphenylpropane, phenolphthalein, resorcinol, andhydroquinone.

As the dichloroanhydrides of dicarboxylic acids, use can be made ofdiacy chlorides of aliphatic dicarboxylic acids such as oxalic acid,glutaric acid, azelaic acid, adipic acid, sebacic acid, fumaric acid;dichloroanhydrides of aromatic dicarboxylic acids such as isophthalicacid, terephthalic acid, diphenyloxide-4,4'-dicarboxylic acid; a mixtureof dichloroanhydrides of fumaric and terephthalic acid, and a mixture ofdichloroanhydrides of isophthalic and terephthalic acids.

As the organic solvents inert relative to diacyl chlorides ofdicarboxylic acids employed for liquefaction of solid (under normalconditions) dichloroanhydrides of dicarboxylic acids, use can be made ofhydrocarbons (such as heptane and benzene), chlorinated hydrocarbons(such as methylenechloride, chloroform, dichloroethane), ethers andesters (such as ethyl ether, tetrahydrofuran), ketones (such as acetone,methylethylketone), anhydrous organic acids (such as formic acid andacetic acid) and the like, though it is most preferable to use methylenechloride (dichloromethane).

The process according to the present invention makes it possible toproduce fibrides of both homopolymers and copolymers using in theprocess of the gas-phase polycondensation both individual diamines,diphenols and dichloroanhydrides of dicarboxylic acids, and mixtures ofdiamines and diacyl chlorides of dicarboxylic acids.

According to the process of the present invention, an aqueous alkalinesolution of bifunctional compounds to be acylated is fed into thereaction chamber as a continuous stream oriented in the horizontal planeof the reaction zone. In doing so, according to the present invention,diacyl chlorides of dicarboxylic acids in a state of super heated vaporwith a carrier are fed into the reaction zone in its vertical plane andcontacting of the reagents is effected in a cross-current underconditions of shear stress.

As the carrier of superheated vapor of diacyl chlorides of dicarboxylicacids in the process according to the present invention use is made ofsuperheated steam or air. The concentration of diacyl chlorides ofdicarboxylic acids supplied into the reaction zone is 0.1 to 5 mol/m³ ofthe carrier.

When the starting reagents are supplied into the reaction zone followingthe procedure according to the present invention, the liquid phase(supplied in the horizontal plane) is contacted with the gas phase(supplied in the vertical plane) in a cross-current manner.

From a thin layer of the liquid phase the acylated bifunctional monomerdiffuses to the phase contact surface, wherein there occurs aninstantaneous or rapid reaction of polycondensation with the formationof a gel-like film of a synthetic hetero-chain polymer, while thelow-molecular substance evolving during the reaction of irreversiblepolycondensation, i.e. hydrogen chloride, diffuses into the aqueousalkaline solution, wherein it is neutralized with an alkali such ascaustic soda. The molar ratio of the monomers in the reaction zone isvaried depending on the accuracy of metering the latter within the rangeof from 1.05 to 2 moles of the monomer to be acylated, e.g. diamine per1 mol of diacyl chloride of a dicarboxylic acid. Due to the fact thatthe polycondensation proceeds under conditions of shear stress caused byhigh speed of the gas and liquid phases and their interaction in thecross-current, there takes place the formation of fibrides from thegel-like film of the synthetized polymer during the film formation underthe effect of shear stress. Under the action of the dynamic head of thegas phase in the reaction zone there occurs inversion of the phases andthe formation of a highly turbulent three-phase mobile foam having ahighly developed surface, whereupon the process of formation of fibridesand chemical processes are completed. The presence of a developedpolymeric matrix of the mobile foam stabilizes it at a linear speed ofthe gas phase exceeding the upper limit of linear speeds of the foamcondition range under the formation of a usual gas-liquid emulsion(two-phase foam).

In the process according to the present invention the polycondensationis to be conducted under a pressure of from 0.5 to 2 atm and at atemperature within the range of from 90° to 105° C.

It has been found that carrying out the process at an elevatedtemperature and superatmosphere pressure in the reaction zone lowerssolubility of diacyl chlorides of dicarboxylic acids in the liquid phaseand the probability of their saponification, and increases the polymeryield.

It has been found advantageous that the linear speed of the carrier ofdiacyl of dicarboxylic acids be within the range of from 2 to 12 m/secand the speed of injection of the continuous stream of the aqueousalkaline solution into the reaction zone be equal to 0.5-6 m/sec.

The process according to the present invention makes it possible toproduce heat-resistant fibrides of aromatic and aliphatic-aromaticheterochain polymer suitable for the manufacture of, for example,synthetic paper for electroengineering applications. The yield offibrides, as calculated for the resulting polymer, is 100% and themolecular mass of the resulting polymer expressed through values oflogarithmic viscosity of a solution of this polymer in sulphuric acid ofthe concentration of 0.5 g/dl is equal to 0.4-1.5 dl/g. The processaccording to the present invention makes it possible to ensureuniformity of particle size of the obtained fibrides.

In accordance with the present invention, it is desirable to carry outthis process in an apparatus comprising a vertically mounted cylindricalhousing 1 (FIG. 1) made of a stainless and refractory steel. The housingcomprises a reaction chamber 2 and, positioned thereunder, a chamber 3for generating the gas phase of the starting products-diacyl chloridesof dicarboxylic acids. The volume of the reaction chamber 2 does notexceed 2-5% of the whole volume of the apparatus. The reaction chamber 2contains means for admitting the liquid phase of the starting products,i.e. an aqueous alkaline solution of bifunctional compounds thereinto tobe acylated as a continuous stream oriented in the horizontal plane ofthe reaction chamber 2.

In one embodiment of the apparatus according to the present inventionthe means for admitting the liquid phase into the reaction chamber 2 isa shell 4 coaxially mounted outside the reaction chamber 2 at such adistance therefrom that a cavity 5 is formed between the external wallof the reaction chamber 2 and the inner wall of the shell 4.

The shell 4 is provided with an inlet pipe 6 for the supply of theliquid phase into the cavity 5. The shell 4 is secured to the reactionchamber 2 by means of threading provided at the external surface of thereaction chamber 2.

The distance at which the shell 4 is spaced from the reaction chamber 2may be equal to, for example, 3-5 mm. In the lower portion of thereaction chamber 2 there is a clearance 7 having its height constantover the entire diameter of the reaction chamber 2 and equal to0.02-0.06 of the diameter of the reaction chamber 2.

Through the clearance 7 the above-mentioned cavity 5 communicates withthe reaction chamber 2. It has been found that the clearance of theabove-specified size ensures the effluence of the aqueous alkalinesolution of the bifunctional monomer to be ocylated into the reactionchamber 2 at a given speed equal, as it has been mentioned hereinabove,to 0.5-6 m/sec. The volume of cavity 5 corresponding to theabove-mentioned distance spacing the shell 4 from the reaction chamber 2ensures a continuous stream of the liquid phase oriented in thehoriziontal plane of the reaction chamber 2.

Besides, in the reaction chamber 2 there is a means ensuring creation ofthe required dynamic head of the gas phase at the site of its contactwith the liquid phase; the head value should be sufficient for the phaseinversion and formation of developed foaming conditions.

This means can be a horizontally mounted in the bottom section of thereaction chamber 2, partition 8 with a live cross-section of from 18 to40%. The perforated partition 8 is mounted in the lower section of thereaction chamber 2 under the clearance 7 at such a distance therefrom,so that the gas phase supplied upwardly in the vertical plane has asufficient kinetic head. This distance should constitute, as it has beenfound according to the present invention, at least 0.015 and at most 0.1the height of the reaction chamber 2.

In accordance with the present invention, the means ensuring creation ofthe required dynamic head of the gas phase at the site of its contactwith the liquid phase can be also embodied as two tapered cones 9 and 10(FIG. 2) positioned in the reaction chamber 2 and substantially shapingit. These tapered cones 9 and 10 are connected therebetween at the siteof the minimum diameter thereof with the formation, at the joint, of aclearance 7 having constant height over the entire diameter of thetapered cone 9 or 10 equal to 0.02-0.06 of the value of the maximumdiameter of cone 9 or 10. It should be noted that these tapered cones 9or 10 should be of such a size which ensures the ratio of the maximumdiameter of one of the tapered cones 9 or 10 to its minimum diameter beequal to 2.5-2:1 and the ratio of the tapered cone height to the minimumdiameter be equal to 4-5:1.

The reaction chamber 2 formed by two tapered cones 9 and 10 has an inletpipe 6 for the supply of the liquid phase of the starting products intothe reaction chamber 2.

The present invention also stipulates the following embodiment of thismeans for admitting the liquid phase into the reaction chamber 2. Thismeans contains a mechanical slit nozzle 11 (FIG. 3) with an openingguide angle of such value which ensures fullness of overlapping of thereaction chamber 2 cross-section (i.e. a continuous flow of the liquidphase is created oriented in the horizontal plane), or with an openingangle of from 110° to 180°. The mechanical slit nozzle 11 is positionedalong the axis of the reaction chamber 2 in such a manner that the slitof said nozzle 11 is spaced at such a distance from the surface of thehorizontal perforated partition 8 at which the gas phase supplied fromthe bottom into the reaction chamber 2 has a dynamic head sufficient forfoaming and fibride-formation. It has been found that the slit of nozzle11 should be positioned over the horizontal perforated partition 8 at adistance therefrom equal to 0.1-0.04 of the height of the reactionchamber 2.

The casing of the nozzle 11 having a turning angle of 90° from thehorizontal to the vertical plane is fixed to the wall of the reactionchamber 2 by means of a threaded joint.

The means for admitting the gas phase into the reaction chamber 2 areprovided in the lower section of the generation chamber 3 and comprise anozzle-type mixer 12 (FIG. 1) comprising a cylindrical housing 13 withan inlet pipe 14 intended for the admission of the carrier and a tuyere15 for the supply of a liquefied diacyl chloride of a dicarboxylic acidinto a diffuser 16 provided with electrical heating members 17. Thediffuser 16 is mounted to an evaporator-superheater 18 comprisingsubstantially the upper portion of the generation chamber 3 by means ofsimple flange joints. The nozzle-type mixer 12 is provided with acommercial pressure gauge 19.

The evaporator-superheater 18 is fixed to the reaction chamber 2positioned thereover by means of a simple flange joint.

Certain embodiments of the apparatus according to the present invention(FIGS. 1 and 3) contemplate the use of a perforated partition 8 in theflange joint.

The means for the withdrawal of the reaction products from the reactionchamber 2 are provided in the upper part thereof in the form of anoutlet pipe 20.

The above-described apparatus according to the present inventionoperates in the following manner.

A liquid or liquefied (as a melt or a concentrated solution) diacylchloride of a dicarboxylic acid is admitted under pressure of an inertgas into the tuyere 15 of the nozzle mixer 12. The liquid effluent fromthe tuyere 15 in the diffuser 16 contacts the carrier (superheated steamor air heated to a temperature above the dichloroanhydride meltingpoint) supplied from the inlet pipe 14. A mist-like aerosol is formeddue to the internal and external heat-exchange which undergoes phasetransformations in the evaporator-superheater 18. The generatedvapor-gas mixture at a temperature equal to or exceeding the boilingtemperature of the bifunctional monomer to be acylated at a givenconcentration thereof in the gas phase is passed onto the perforatedpartition 8 (FIGS. 1 and 3) or into the tapered cone 9 or 10 locateddirectly over the generation chamber 3 (FIG. 2). The speed at which thegenerated vapor-gas mixture passes into the lower part of the reactionzone 2 is equal to 2-12 m/sec. However, due to the fact that in thelower part of the reaction chamber the vertically ascending vapor-gasstream is contacted with the horizontal perforated partition 8 (FIGS. 1and 3) or passes into the tapered cone 9 with its volume decreasing atthe top, there is observed an increase of the linear speed of thevapor-gas stream. The kinetic energy of the vapour-gas stream isincreased proportionally to the square of increase in its linear speed.

Simultaneously with the introduction, into the generation chamber, of avapor-gas mixture of a diacyl chloride of a dicarboxylic acid, throughthe inlet pipe 6 into the cavity 5 formed between the outer wall of thereaction chamber 2 and the inner wall of the shell 4 (FIGS. 1 and 2) orthrough the duct of the mechanical slit nozzle 11 (FIG. 3) there isadmitted an aqueous-alkaline solution of a bifunctional monomer to beacylated (liquid phase). The liquid phase is supplied under a head equalto the pressure in the reaction chamber 2 created by a centrifugal pump(not shown). Due to the presence of the clearance 7 through which thecavity 5 communicates with the reaction chamber 2, the flow of theaqueous-alkaline solution of the bifunctional monomer to be acylated isfed, strictly in the horizontal plane, into the reaction chamber 2(FIGS. 1 and 2) as a continuous thin film at a speed of from 0.5 to 6m/sec. In the case of admitting the aqueous alkaline solution of thebifunctional monomer to be acylated into the reaction chamber 2 throughthe mechanical slit nozzle 11, there also occurs the formation of a thincontinuous film of the liquid phase admitted into the reaction chamberat a speed of from 0.5 to 6 m/sec.

Therefore, at a distance from the surface of the perforated partition 8equal to 0.015-0.1 of the height of the reaction chamber or directlyover the upper part of the narrow portion of the tapered cone 9 (FIG. 2)there occurs the interaction of the liquid and gas phases under the mostintensive hydrodynamic conditions. At the same time there takes placechemical processes of polycondensation with the formation of a polymericfilm and neutralization of the evolving low-molecular substance,hydrogen chloride. Due to the high kinetic energy of the vapor-gasstream accumulated upon passing the latter through the perforatedpartition 8 or narrow portion of the tapered cone 9, as well as the highrate of effluence of the liquid phase from the annular slit 7, in thecross-counter contact of the liquid and gas phase there are considerableshear stresses, thus ensuring the formation of long-fiber fibridesdirectly in the reaction chamber 2 from the polymeric film obtained as aresult of interaction of the starting components. In the bulk of thehighly-turbulent mobile layer of three-phase foam withdrawn from thereaction chamber 2 by the kinetic stream of the vapor-gas phase throughthe outlet pipe 20 into a collecting separator (not shown) there occurfurther processes of propagation and rupture of the polymeric chain andfibride- formation.

It should be noted that the process of forming a polymericfilm-polycondensation should be preferably carried out at a pressure offrom 0.5 to 2 atm at a temperature within the range of from 90° to 105°C.

For a better understanding of the present invention the followingspecific examples are given hereinbelow by way of illustration.

EXAMPLE 1

A 0.1 M aqueous-alkaline solution of hexamethylenediamine at a volumerate of 452 l/hr and concentration of caustic soda of 0.13 mol/lpreheated to a temperature of 99°-102° C. is fed through the radialinlet pipe into the cavity 5 formed between the reaction chamber 2 andthe shell 4 (inside diameter of the reaction chamber is 50 mm) anduniformly over the entire circumference exits at a speed of 0.94 m/secthrough the clearance 7 into the reaction chamber 2 forming a continuousfilm of the liquid phase at a distance of 4 mm from the surface of theperforated partition 8. A solution of terephthalic acid diacyl chloridein methylene chloride with a concentration of 400 g/l and at a volumerate of 11.5 l/hr at a nitrogen pressure of 3.5 atm.g. is fed into thetuyere 15 of the nozzle mixer 12. The liquid torch effluent from thetuyere 15 in the diffuser 16 is contacted with air supplied through theinlet pipe 14 at a rate of 56.5 m³ /hr while being preheated to atemperature of 160° C. Upon the interaction of the streams there isformed a mist-like aerosol of terephthalic acid diacyl chloride which isfurther converted in the chamber 3 for generation of the gas phase intoa vapor-gas mixture superheated to a temperature of 190° C. At thistemperature the vapor-gas mixture through the perforated partition 8with a free section of 25% is passed to the reaction chamber 2 andcontacted with the liquid phase at a molar ratio of the monomers in thecontacting phases of 2:1 (excess of hexamethylenediamine). Under apressure of 2 atm.g. there occur chemical reactions of polyamidation andneutralization. From the resulting gel-like film ofpolyhexamethyleneterephthalamide (polyamide-6T) under the effect ofshear stress from contact between the phases, fibrides are formed. Thereaction mass is passed into a collecting separator through the outletpipe 20 by the dynamic head of the gas stream. Inert gases, water vaporsand vapors of methylene chloride are fed to a cooling condenser througha hollow shaft of the foam suppressor. The water condensate and that ofmethylene chloride from the drop deflector are delivered to separationand air is vented to the atmosphere. The aqueous suspension is fed intoa receiving filter. The filtrate with the content ofhexamethylenediamine of 0.05 mol/l is fed by means of a centrifugal pumpto the collector of the liquid phase and fibrides are washed with waterto a neutral reaction, compressed in a centrifuge to a moisture contentof 82% and packed into polyethylene bags.

The logarithmic viscosity of a solution of the polymer in sulphuric acidwith a concentration of 0.5 g/dl is 1.1 dl/g.

The yield of polyhexamethyleneterephthalamide as calculated onterephthalic acid diacyl chloride is 98%, the yield of fibrides ascalculated for the resulting polyhexamethyleneterephthalamide is 96%.The Shopper-Riegler fineness of the fibrides is 90°.

EXAMPLE 2

Under conditions similar to those described in the foregoing Example 1,from hexamethylenediamine and terephthalic acid diacyl chloridepolyhexamethyleneterephthalamide is produced with the only differencebeing that the molar ratio of hexamethylenediamine to terephthalic aciddichloroanhydride is maintained equal to 1.1:1.

The logarithmic viscosity of the polymer solution in sulphuric acid witha concentration of 0.5 g/dl is 1 dl/g. The yield of the polymer ascalculated for terephthalic acid diacyl chloride is 95%, the and yieldof fibrides as calculated for the resultingpolyhexamethyleneterephthalamide is 96%. The Shopper-Riegler fineness ofthe fibrides is 90°.

EXAMPLE 3

Under conditions similar to those described in Example 1, fromhexamethylenediamine and terephthalic acid diacyl chloridepolyhexamethyleneterephthalamide is obtained with the only differencebeing that for the gas phase generation use is made of a melt ofterephthalic acid diacyl chloride at a temperature of 130° C. Theconcentration of terephthalic acid diacyl chloride in the gas phase is0.93 mol/m³. The molar ratio of the monomers in the contacting phases is1.5:1 (excess of hexamethylenediamine), the speed of effluence of theliquid phase from the annular slit into the reaction zone is 1.2 m/sec.The gas phase temperature at the inlet into the reaction chamber 2 is170° C. The logarithmic viscosity of the polymer solution in sulphuricacid with concentration of 0.5 g/dl is 0.96 dl/g. The yield of thepolymer as calculated for terephthalic acid diacyl chloride is 99%. TheShopper-Riegler fineness of fibrides is 85°. The average weighed lengthof the fibrides is 170 dcg.

EXAMPLE 4

A 0.1 M aqueous alkaline solution of hexamethylenediamine at volume rateof 452 l/hr and concentration of caustic soda of 0.13 mol/l preheated toa temperature of 99°-102° C. is fed through the radial inlet pipe 6 intothe cavity 5 formed between the reaction chamber 2 and shell 4 (theinside diameter of the reaction chamber 2 is 50 mm) and exits, uniformlyalong the entire circumference, at speed of 5.94 m/sec through theclearance 7 into the reaction chamber 2 while forming a continuous filmof liquid phase at distance of 4 mm from the surface of the perforatedpartition 8. The melt of terephthalic acid diacyl chloride having atemperature of 130° C. at the volume rate of 11.5 l/hr at a pressure of3.5 atm.g. is fed into the tuyere 15 of the nozzle-type mixer 12. Theliquid torch effluent from the tuyere 15 is contacted in the diffuser 16with air supplied through the inlet pipe 14 at a volume rate of 56.3 m³/hr and preheated to a temperature of 160° C. The concentration ofterephthalic acid diacyl chloride in the gas phase is 4 mol/m³. Upon theinteraction of the streams there is formed a mist-like aerosol ofterephthalic acid diacyl chloride further converted, in the gas-phasegeneration chamber 3, to a vapor-gas mixture superheated to atemperature of 200° C. At this temperature the vapor-gas mixture throughthe perforated partition 8 with a live cross-section of 25% is passed tothe reaction chamber 2 and contacted with the liquid phase at a molarratio of the monomers in the contacting phases of 1.1:1 (excess ofhexamethylenediamine). In doing so, at a pressure of 2 atm there occurchemical reactions of polyamidation and neutralization. From theresulting gel-like film of polyhexamethyleneterephthalamide(polyamide-6T), fibrides are formed under the effect of the shear stressoriginating upon the contact between the phases. The reaction mass isfed to a collecting separator through the outlet pipe 20 by means of thedynamic head of the gas stream. Inert gases, vapors of water through ahollow shaft of the foam suppressor are delivered to a coolingcondenser. The condensate of water after the drop deflector is deliveredto separation while air is vented to the atmosphere. The aqueoussuspension is fed to a receiving filter. The filtrate with the contentof hexamethylenediamine of 0.05 mol/l is fed to the collector of theliquid phase. The fibrides are washed with water to a neutral reaction,compressed in a centrifuge to a moisture content of 82% and packed intopolyethylene bags.

The logarithmic viscosity of the polymer solution in sulphuric acid witha concentration of 0.5 g/dl is 0.8 dl/g. The yield of the polymer ascalculated for terephthalic acid anhydride is 90%, the yield of fibridesas calculated for the resulting polyhexamethyleneterephthalamide is100%. The degree of fineness (according to Shopper-Riegler) is 100°, theaverage weighed length thereof is 165 dcg.

EXAMPLE 5

Under the conditions similar to those described in Example 1, fromhexamethylenediamine and isophthalic acid diacyl chloridepolyhexamethyleneisophthalamide is obtained.

The logarithmic viscosity of the polymer solution in sulphuric acid withthe concentration of 0.5 g/dl is 0.76 dl/g. The yield ofpolyhexamethyleneisophthalamide as calculated for isophthalic aciddiacyl chloride is 99.9%. The yield of fibrides as calculated for theobtained polyhexamethyleneisophthalamide is 100%. The degree of fineness(Shopper-Riegler) of the fibrides is 60°. The polymer melting point is205° C.

EXAMPLE 6

Under conditions similar to those described in Example 1, fromhexamethylenediamine and a mixture of diacyl chlorides of isophthalicand terephthalic acids taken in a ratio of 1:1, there is obtained acopolyamide of hexamethylenediamine and dichloroanhydrides ofisophthalic and terephthalic acids.

The logarithmic viscosity of the polymer solution in sulphuric acid witha concentration of 0.5 g/dl is 0.7 dl/g. The polymer yield as calculatedfor the total of dichloroanhydrides of isophthalic acid and terephthalicacid is 97%, the yield of fibrides as calculated for the obtainedcopolyamide is 100%. The degree of fineness (Shopper-Riegler) of thefibrides is 70°. The melting point of the polymer is 280° C.

EXAMPLE 7

A 0.1 M aqueous alkaline solution of hexamethylenediamine preheated to atemperature of 99° C. is fed, at a volume rate of 788 l/hr, into anannular clearance 7 with a height of 1.5 mm formed between tapered cones9 and 10 having the minimum diameter of 25 mm. The gas phase generatedfrom the melt of terephthalic acid diacyl chloride and containing 0.93mol/m³ of carrier (air) for terephthalic acid diacyl chloride iscontinuously fed at a volume rate of 56.5 m³ /hr into the tapered cone 9of the reaction chamber 2. Its temperature at the inlet of the reactionchamber 2 is 150° C. The resulting fibrides ofpolyhexamethyleneterephthalamide in the composition of the reaction massare subjected to a further treatment following the procedure describedin Example 1 hereinbefore.

The logarithmic viscosity of the polymer solution in sulphuric acid witha concentration of 0.5 g/dl is equal to 1.06 dl/g. The yield ofpolyhexamethyleneterephthalamide as calculated for terephthalic aciddiacyl chloride is 98%, the yield of fibrides as calculated for theobtained polyhexamethyleneterephthalamide is 99%. The Shopper-Rieglerfineness of the fibrides is 100°; their average weighed length is 156dcg.

EXAMPLE 8

Under conditions similar to those specified in Example 7, fromhexamethylenediamine and a mixture of diacyl chlorides containing 9parts by weight of isophthalic acid diacyl chloride, there is obtained acopolyamide of hexamethylene and diacyl chlorides of isophthalic andterephthalic acids. The logarithmic viscosity of the polymer solution insulphuric acid with a concentration of 0.5 g/dl is equal to 1.06 dl/g.The yield of the copolyamide as calculated for the total diacylchlorides of terephthalic and isophthalic acids is 95%, the yield offibrides as calculated for the resulting copolyamide is 100%. TheShopper-Riegler fineness of the fibrides is 84°.

EXAMPLE 9

Under conditions similar to those specified in Example 7, fromhexamethylenediamine and a mixture of diacyl chlorides containing 4parts by weight of terephthalic acid diacyl chloride and 1 part byweight of isophthalic acid diacyl chloride, there is obtained acopolyamide of hexamethylenediamine and diacyl chlorides of terephthalicand isophthalic acids. The logarithmic viscosity of the polymer solutionin sulphuric acid with a concentration of 0.5 g/dl is 1.2 dl/g. Theyield of the copolyamide as calculated for the total of diacyl chloridesof terephthalic and isophthalic acids is 99%, the yield of fibridesbased on the produced copolyamide is 100%. The Shopper-Riegler finenessof the fibrides is 80°.

EXAMPLE 10

Under conditions similar to those of Example 7, fromhexamethylenediamine and a mixture of diacyl chlorides containing 3parts by weight of terephthalic acid diacyl chloride and 1 part byweight of isophthalic acid diacyl chloride, a copolyamide ofhexamethylenediamine and diacyl chloride of terephthalic and isophthalicacids is obtained. The logarithmic viscosity of the polymer solution insulphuric acid with a concentration of 0.5 g/dl is 1.06 dl/g. The yieldof the copolyamide as calculated for the total dichloroanhydrides ofterephthalic and isophthalic acids is 94%, the yield of fibrides ascalculated for the obtained copolyamide is 99%. The Shopper-Rieglerfineness of the fibrides is 75°.

EXAMPLE 11

Under conditions similar to those described in Example 7, frommetaxylylenediamine and terephthalic acid diacyl chloridepoly-meta-xylyleneterephthalamide is obtained. The logarithmic viscosityof the polymer solution in sulphuric acid with a concentration of 0.5g/dl is 0.44 dl/g. The yield of poly-meta-xylyleneterephthalamide ascalculated for terephthalic acid diacyl chloride is 90%, the yield offibrides as calculated for the obtainedpoly-meta-xylyleneterephthalamide is 95%. The Shopper-Riegler finenessof the fibrides is 70°.

EXAMPLE 12

Under conditions similar to those of Example 7, from metaxylylenediamineand isophthalic acid diacyl chloride poly-meta-xylyleneisophthalamide isobtained. The logarithmic viscosity of the polymer solution in sulphuricacid with a concentration of 0.5 g/dl is 0.7 dl/g. The yield ofpoly-meta-xylyleneisophthalamide, as calculated for isophthalic aciddiacyl chloride, is 95%, the yield of the fibrides as calculated for theobtained poly-meta-xylyleneisophthalamide is 98%. The Shopper-Rieglerfineness of the fibrides is 75°.

EXAMPLE 13

Under conditions similar to those described in Example 7, from a mixturecontaining 75% of meta-xylylenediamine and 25% of para-xylylenediamine,and terephthalic acid diacyl chloride there is obtained a copolyamide ofmeta- and paraxylylenediamine and terephthalic acid diacyl chloride. Thelogarithmic viscosity of the polymer solution in sulphuric acid with aconcentration of 0.5 g/dl is 0.12 dl/g. The yield of the copolyamide is80% as calculated for terephthalic acid diacyl chloride. The fibrideshave a small particle size. The Shopper-Riegler fineness is 50°.

EXAMPLE 14

Under conditions similar to those specified in Example 7, from a mixturecontaining 75% of meta-xylylenediamine and 25% of para-xylylenediamineand isophthalic acid diacyl chloride there, is obtained a copolyamide ofmeta- and para-xylylenediamines and isophthalic acid diacyl chloride.The logarithmic viscosity of the polymer solution in sulphuric acid witha concentration of 0.5 g/dl is equal to 0.4 dl/g. The yield of thecopolymamide as calculated for isophthalic acid diacyl chloride is 91%.The Shopper-Riegler fineness of the fibrides is 70°.

EXAMPLE 15

Under conditions similar to those specified in Example 1, fromhexamethylenediamine and oxalic acid diacyl chloride, except that in thegas phase there is a lack of organic solvent and the gas phasetemperature at the inlet of the reaction chamber 2 is equal to 125° C.,and polyhexamethyleneoxamide is obtained. The logarithmic viscosity ofthe polymer solution in sulphuric acid with a concentration of 0.5 g/dlis 1.5 dl/g. The yield of polyhexamethyleneoxamide as calculated foroxalic acid diacyl chloride is 99%. The yield of fibrides based on theresulting polyhexamethyleneoxamide is 100%. The Shopper-Riegler finenessof the fibrides is 95°.

EXAMPLE 16

A 0.1 M aqueous alkaline solution of hexamethylenediamine at a volumerate of 452 l/hr and a concentration of caustic soda of 0.13 mol/lpreheated to a temperature of 99°-102° C. is passed through the radialinlet pipe 6 into the cavity 5 formed between the reaction chamber 2 andshell 4 (inside diameter of the reaction chamber is 50 mm) and uniformlyexits over the entire circumference at a rate of 0.94 m/sec through theclearance 7 into the reaction chamber 2 forming a continuous curtain ofthe liquid phase at a distance of 4 mm from the surface of theperforated partition 8. Glutaric acid diacyl chloride at a volume rateof 11.5 l/hr under nitrogen pressure of 3.5 atm.g. is fed into thetuyere 15 of the nozzle mixer 12. The liquid torch effluent from thetuyere 15 is contacted in the diffuser 16 with air supplied through theinlet pipe 14 at a volume rate of 56.5 m³ and preheated to a temperatureof 160° C. Upon the interaction of the streams there is formed amist-like aerosol of glutaric acid diacyl chloride which is furtherconverted, in the gas-phase generation chamber 3, into a vapor-gasmixture superheated to a temperature of 125° C. At this temperature thevapor-gas mixture through the perforated partition 8 with the livecross-section of 25% is passed into the reaction chamber 2 and contactedwith the liquid phase at a molar ratio of the monomers in the contactingphases of 2:1 (excess of hexamethylenediamine). In doing so, under thepressure of 2 atm.g. there occur chemical reactions of polyamidation andneutralization. From the resulting gel-like film ofpolyhexamethyleneglutaramide, fibrides are formed under the effect ofthe shear stress originating upon phase contact. The reaction mass ispassed into a collecting separator through the outlet pipe 20 by thedynamic head of the gas stream. Inert gases, water vapors pass through ahollow shaft of foam suppressor and are delivered into a coolingcondenser. The aqueous suspension is fed into a receiving filter. Thefiltrate with a content of hexamethylenediamine of 0.05 mol/l is fed bymeans of a centrifugal pump into a liquid-phase collector, whilefibrides are washed with water to a neutral reaction and compressed in acentrifuge to a moisture content of 82% and packed into polyethylenebags.

The logarithmic viscosity of the polymer solution in sulphuric acid witha concentration of 0.5 g/dl is equal to 1.4 dl/g. The yield ofpolyhexamethyleneglutaramide as calculated for glutaric acid diacylchloride is 98%, the yield of fibrides as calculated for the obtainedpolyhexamethyleneglutaramide is 100%. The Shopper-Riegler fineness ofthe fibrides is 92°.

EXAMPLE 17

A 0.2 M aqueous alkaline solution of hexamethylenediamine with atemperature of 90° C. and a volume rate of 170 l/hr is fed into thecavity 5, wherefrom this solution uniformly along the entirecircumference of the clearance 7 exits at a rate of 0.5 m/sec into thereaction chamber 2. The solution of terephthalic acid diacyl chloride inmethylene chloride with a concentration of 400 g/l and a volume rate of8.6 l/hr at an inert gas (nitrogen) pressure of 4.5 atm.g. is fed intothe tuyere 15 of a pneumatic nozzle. The liquid torch effluent from thenozzle is contacted in the diffuser 16 with steam supplied through theinlet pipe at the weight rate of 64 kg/hr at a pressure of 3 atm.g. andheated to a temperature of 149° C. Upon the interaction of the streamsthere is formed a fine dispersion of terephthalic acid diacyl chloridein the superheated steam which is further converted, while moving in thevertical plane along the heating surfaces of the gas-phase generationchamber 3, to a vapor-gas mixture heated to a temperature of 200° C. Atthis temperature and a monomer concentration of 0.6 mol/m³ of thecarrier, the vapor phase through perforations of the partition 8 with afree cross-section of 25% passes into the reaction chamber 2 and iscontacted with the liquid phase in a state of continuous flow orientedin the horizontal plane of the reaction chamber 2. At a pressure of 2atm.g. in the reaction chamber 2 there occur chemical reactions ofpolyamidation and neutralization, as well as the process of formingfibrides from the gel-like film of the polyamide. A portion of steam iscondensed upon contacting the liquid phase, the additional condensateimproves the conditions of transportation of the reaction polymer mass,lowers the total consumption of the carrier of the liquid phase andmakes it possible to increase the monomer concentration therein. Thereaction mass is transported, under steam pressure, into a collectingseparator through an intermediate cooler, wherein the major portion ofsteam is condensed. The non-condensed steam and vapors ofmethylenechloride are fed, through a hollow shaft of the deskimmer, intoa cooling condenser. The condensate is accumulated in a drop-deflectormounted before the atmospheric stack and recycled to the process for thepreparation of the starting solution of terephthalic acid diacylchloride. The aqueous suspension of the polymer under pressure iscontinuously withdrawn from the collecting separator into the receivingfilter, wherein the polymer is separated from the aqueous alkalinesolution of hexamethylenediamine, washed, squeezed in a centrifuge andpacked. The filtrate diluted with the process steam condensate isrecycled to the process for the preparation of the starting aqueousalkaline solution of hexamethylenediamine.

The resulting polyhexamethyleneterephthalamide has the form offilament-film fibrides; the yield thereof is 91%. The logarithmicviscosity of the polymer solution in sulphuric acid with a concentrationof 0.5 g/dl is 0.64 dl/g. The Shopper-Riegler fineness of the fibridesis 92°.

EXAMPLE 18

Under conditions similar to those described in the foregoing Example 17,a 0.1 M aqueous alkaline solution of hexamethylenediamine preheated to atemperature of 90° C. is fed into the reaction chamber 2 at a volumerate of 230 l/hr. The generated vapor phase with a concentration ofterephthalic acid diacyl chloride of 0.2 mol/m³ is continuously fed,under a total pressure of 1 atm.g. with a weight rate of the carrier(steam) superheated to a temperature of 145° C., of 120 kg/hr, throughthe perforations of the partition 8 into the reaction chamber 2, whereinit reacts with the liquid phase. Separation of the reaction mass at theswitched-off centrifugal foam suppressor takes place in the receivingfilter communicating with the atmosphere through a vent pipe.

The resulting product-fine fibrides with a highly developed surface areaand Shopper-Riegler fineness of 80°. The yield ofpolyhexamethyleneterephthalamide is 89%. The logarithmic viscosity ofthe polymer solution in sulphuric acid with a concentration of 0.5 g/dlis equal to 0.48 dl/g.

EXAMPLE 19

Under conditions similar to those specified in Example 17, fromhexamethylenediamine and terephthalic acid dichloroanhydridepolyhexamethyleneterephthalamide is obtained, with the only differencebeing that generation of the gas phase is effected from a melt ofterephthalic acid diacyl chloride superheated to a temperature of 146°C. and steam at a pressure of 4 atm.g. superheated to a temperature of200° C. The contact of the reacting phases occurs at the site of thejunction of the tapered cones 9 and 10. The entire steam is condensed inan intermediate cooler mounted between the reaction chamber 2 and areceiving filter connected to the atmosphere. There is no exhaust to theatmosphere, the sections of foam-suppression and condensation areabsent. The process steam condensate with the filtrate is recycled tothe process for the preparation of the liquid phase of the startingproducts. The logarithmic viscosity of the solution of the polymer insulphuric acid with a concentration of 0.5 g/dl is equal to 0.9 dl/g.The resulting fibrides are thin fibers with a Shopper-Riegler finenessof 90°, and mean average length of 138 dcg. The yield ofpolyhexamethyleneterephthalamide is equal to 96% as calculated forterephthalic acid dichloroanhydride.

EXAMPLE 20

A 0.1 M aqueous alkaline solution of 4,4'-dihydroxydiphenylpropane witha volume rate of 209 l/hr and a temperature of 102° C. is fed by meansof a centrifugal pump into the cavity 5 between the reaction chamber 2and the shell 4, wherefrom it exits at the rate of 0.5 m/sec into thereaction chamber 2 through the clearance 7 with a diameter of 50 mm anda height of 0.7 mm. Air heated to a temperature of 160° C. with a volumerate of 15 m³ /hr is passed through the inlet pipe 14 into the diffuser16 and serves to disperse, to an aerosol state, isophthalic acid diacylchloride supplied under a nitrogen pressure of 3.5 atm.g. through thetuyere 15 into the diffuser 16 in the state of a superheated melt at avolume rate of 5.3 l/hr. The vapor-gas mixture generated in theevaporator-superheater 18 is fed at a temperature of 200° C. throughperforations of the partition 8 with a free cross-section of 25 % intothe reaction chamber 2, wherein it is contacted with the aqueousalkaline solution of 4,4'-dihydroxydiphenylpropane. The three-phasemobile foam formed as a result of said chemical and physical processesand containing polymeric particles ofpoly-4,4'-dihydroxydiphenylpropaneisophthalate (polyarylate D-1) iswithdrawn from the reaction chamber 2 by the dynamic flow of the gasphase and then subjected to separation. The aqueous suspension of thepolyarylate is filtered, the separated polymer is washed, dried andpacked.

The logarithmic viscosity of a 0.5% solution of the resulting polymer ina mixture of 60 parts by weight of phenol and 40 parts by weight oftetrachloroethane is 0.35 dl/g. The fibrides are of a small particlesize. The yield of poly-4,4'-dihydroxydiphenylpropaneisophthalate is77.6% as calculated on isophthalic acid diacyl chloride. TheShopper-Riegler fineness is 40°.

EXAMPLE 21

Under conditions similar to those described in Example 20, from4,4'-dihydroxydiphenylpropane and terephthalic acid dichloroanhydridethere is obtained poly-4,4'-dihydroxydiphenylpropaneterephthalate(polyarylate D-2).

The logarithmic viscosity of a 0.5% solution of the resulting polymer ina mixture of 60 parts by weight of phenol and 40 parts by weight oftetrachloroethane is equal to 0.3 dl/g. The resulting fibrides have asmall particle size. The yield ofpoly-4,4'-dihydroxydiphenylpropaneterephthalate is 75% as calculated forterephthalic acid diacyl chloride. The Shopper-Riegler fineness is 35°.

EXAMPLE 22

Under the conditions similar to those described in the foregoing Example20, from 4,4'-dihydroxydiphenylpropane and a mixture of diacyl chloridesof isophthalic and terephthalic acids in the ratio of 1:1 there isobtained a copolyarylate of diphenylpropane and diacyl chlorides of iso-and terephthalic acids. The logarithmic viscosity of a 0.5% solution ofthe copolyarylate in a mixture of 60 parts by weight of phenol and 40parts by weight of tetrachloroethane is 0.32 dl/g. The yield of thecopolyarylate is 76% as calculated for the total amount of the reacteddiacyl chlorides of phthalic acids. The Shopper-Riegler fineness is 40°.

What is claimed is:
 1. A process for producing fibrides of a syntheticheterochain polymer comprising:the polycondensation of a thin filmliquid stream of an aqueous alkaline solution of at least onebifunctional compound to be acylated with superheated vapors of at leastone diacyl halide of a dicarboxylic acid; said bifunctional compoundsupplied to the reaction zone as a continuous thin film liquid streamoriented in the horizontal plane of the reaction zone; said diacylhalide of a dicarboxylic acid supplied to the vertical plane of thereaction zone with a stream of carrier gas; the contacting andpolycondensation of the reagents occurring at the gas-liquid interfacein a cross-current stream under conditions of shear stress; andrecovering the substantially totally fibride polycondensation product.2. The process of claim 1, wherein said bifunctional compound is amonomer selected from the group consisting of diamines and dihydricphenols.
 3. The process of claim 2, wherein the diamines are selectedfrom the group consisting of ethylenediamine, tetramethylenediamine,hexamethylenediamine, dodecamethylenediamine, a mixture ofethylenediamine with hexamethylenediamine, piperazine, N,β-aminoethylenepiperazine, methylpiperazine, metaxylylenediamine,para-xylylenediamine, and a mixture of para and meta-xylylenediamines.4. The process of claim 2, wherein the dihydric phenols are selectedfrom the group consisting of 4,4'-dihydroxydiphenylpropane,phenolphthalein, resorcinol, and hydroquinone.
 5. The process of claim1, wherein the diacyl chlorides of dicarboxylic acids are selected fromthe group consisting of oxalic acid, glutaric acid, azelaic acid, adipicacid, sebacic acid, fumaric acid, isophthalic acid, terephthalic acid,diphenyloxide-4,4'-dicarboxylic acid, mixtures of fumaric andterephthalic acid, and mixtures of isophthalic and terephthalic acids.6. The process of claim 1, wherein the carrier of the superheated vaporof diacyl chlorides of dicarboxylic acids is selected from the groupconsisting of steam, air, and mixtures thereof.
 7. The process of claim1, wherein the concentration of the diacyl chlorides of dicarboxylicacids supplied into the reaction zone is about 0.1 to 5 mol/m³ of thecarrier.
 8. The process of claim 1, wherein the polycondensation isconducted at a pressure of about 0.5 to 2 atm and a temperature of about90° to 105° C.
 9. The process of claim 1, wherein the linear speed ofthe stream of diacyl chlorides of dicarboxylic acids is about 2 to 12m/sec and the speed of the continuous stream of the aqueous alkalinesolution into the reaction zone is about 0.5 to 6 m/sec.